I just recently purchased my first diesel pickup. It's an 82 6.2 1/2 ton with a 3 speed manual with overdrive (not the best tranny I found out, it went south this weekend). Anyway, I changed the oil on the truck right when I bought it. It was pretty black then, and I figured, it couldn't hurt, cuz who knows how long it had been. I've put about 1,000 miles on it since the change, and it's already as black as night again. Is this a normal trait with diesel engines? Should I be using a different oil, maybe a non detergient type? I don't think that's a good idea, since the junk that they detergient oil suspends in it would just be sitting in the engine somewhere else. This motor doesn't seem to have anything wrong with it. It runs great, starts right up every time, has pleanty of power, doesn't smoke too much, and gets me between 18 and 20 miles to the gallon (good info for all those gas mileage woes that I've been seeing on.) Anyhoo, info would be appreciated. Thanks guys.